we're about to hear what that is and find out the best places in america to raise an outdoor kid. jonathan dorn is editor in chief of backpacker magazine, and he is back with us this morning. good to see you again. you call it nature deficit disorder, which is what exactly? >> as you know, it's not an official medical condition, but it's a term that was popularized by richard liu, the author of "last child in the woods." it's used to describe the fact that the alarming increase we see in childhood obesity and attention deficit disorder over the last quarter century is related to the fact that for the first time in history, most of our kids are growing up without a real connection to nature. >> most of them are growing up in cities. >> and they're not getting it through work, through play, through outdoor education. as a result, one in five kids now in the u.s. is considered overweight by the cdc. >> which is an epidemic. let's talk about the best cities in the country to raise an outdoor kid, and a place that i used to live, this makes all the sense in the world to me, is boulder.